Ernst hxteter



Dec. 24, 1929. E, HUETER 1,740,651

SOUND GENERATOR Filed Jan. 30. 1925 5" ksr-W- -H- aw+ ,Z'nvenow EYnSHllefer 1749.2'. .2 //Q, mm

'45 of the system.

Patented Dee. 24, .1929 l UNITED STATES PAT-ENT Aorriciz' ERNST HUETER,oF DARMSTADT, GERMANY soUND GENERATOR The present invention refers todiaphragms which, for practical reasons ,'are mainly used as generators,viz fiat or differently shaped objects, actuated mechanically or byelec.-

6 tricity. Such generator diaphragms have the disadvantage-of notreproducing speech and music accurately, for instance, owing todistortion. These distortions are principally due to the resonancepropensities of the 10 regular diaphragm, inasmuch ason one hand,

sound frequencies near the natural frequency of the respective diaphragmare, relat1vely,

reproducedmuch louder than sounds beyond this zone; and on theother'hand, the natural '15 vibrations of the object rise above theforced,y

i. e. the intended vibration. All of this is based upon the fact thatthe diaphragm has a mass, as well as resettingpower, and thus becomes a.vibrating system (a diaphragm actuated in one'direction'by the impulseto be reproducedA and in the oppositedirection by the resiliency ofthediaphragm).

That is to say, if t-he mass of the diaphragm is great, resonance makesthe energy required to oscillate the diaphragm large and a large forceis necessary to return the diaphragm.

after it is deflected. If the weightof the diaphragm can be made small,the requiredresetting force inherent in the diaphragm may becorrespondingly small. The diaphragm thus requires a smaller force tooperate, it may be less rigid, and

made thinner.

The object of the present invention is the 'creation of a diaphragmshowing a non-pronounced resonance curve, i. e. one as flat as.

possible, in order to warrant a better reproduction', as free fromdistortion as possible, thereby causing a quicker succession of the 40natural vibrations. fAccordingto the invention this end is gained bythereduced weight 'of the vibrating system, whereby the resetting powerAmay be reduced in the same degrec, without changing the naturalfrequency Generally' speaking, the natural frequency of a system servingas a generator, unless one is willing to stand a number of drawbacks,must be near the center of the register of speech frequencies..-.According to the present invention, by the specificconstrucaccordingly may be ApplicationY tiled January 30, 1925', SerialNo. 5,8327, and in Germany Ianuaryr'22, 1924.

tion of the diaphragm, one succeeds iu greatly reducingtlie weight ofthe system, and at the same time in retaining such anamount of theresetting poweras to keep the natural frequency of the diaphragm lesspronounced within the desired zone, which leads to Aan improved-reproduction of the sound.

The diaphragm of the invention consists of a (lattice) network, soarranged as to have ,a relatively large expansion vertically to the sodiaphragm plane, and upon which, as a working diaphragm, a homogeneousmaterial is placed, in order to secure -the'required {irmness',v at thesmallest weight. l j The annexed drawing shows a generator diaphragmcorresponding to the invention, in

two forms:

Fig. 1 is a v'ention.

Fig. 2,is a cross sectional view on line 2.-2 70 ofFigl.A Y Fig. 3 is alan vie7 of a' second form ot my invention taiien on line .3 3 of Fig.4. Fig. 4 is a cross sectional view of the second form of my inventionon' line 4 4 of Fig. 3 75 with the Vupper plate removed to facilitateillustration.

In the form shown in Figs. land 2, the diaphragm consists of plate 1, towhich a number of reinforcing stays 2 have been attached. so These staysneed not be arranged symmetrically. They may be placed irregularly,thereby obtainingv a greater number of d- -visional natural frequencies.A .reinforcing plan view of one form of my inring 3 is provided aboutthe periphery of said 85 A diaphragm. i

A diaphragm with a relatively great resetting power, of light weight, isproduced by employing the` principles'of my invention. Iron foil, forinstance, may be used for the v90 material of the`diaphragm, as thiswillobviate an incr'ease in the eflicient weight, wlii hI would followthrough additional iron plates'f-s orfother armature needed Vwhereverthe diaphragm is actuated by magnetic power. If in such case the foil isnot strong enough to receivethe magnet-ic power lines, it may bereinforced by additional layers, in the respetive place, or by usingheavier foil from the beginning. f

'l One form osuch arrangement is shown in F i`gs..3 and 4. The dia hragmconsists of plates 4 and', made o suitable material," which platesareseparated by network 5., and.

reinforcing ring 8.-

The coverings for itself is very {lightinweight In one ot tlie preferredforms of the :inventionpthe plate'lV is made of'a thin woodlayer withWooden A slats. lIn Fig. 3 the plates 4 and 6 are'thin wooden layers andthe lattice work 5 and the riml8 are of Woodor otherlight Weight porousY material. I have obtained successful 'opera-,

tionwith' thejplates 4 and 6 constructed of palfr and the. lattice work5 and rirn 8 .of cor Such diaphragms, Awithout great increase in Weight,may be made large enough to dispense with anA acoustic horn or amplifierto `secure the-required sound effect.

Claims:` '1. A sound reproducer having a diaphragm'comprising a shect'ofelastic material and `aplurality of reinforcing members of porousmaterial and a second sheet of elastic material secured to saidreinforcing members in spaced relation to saidffirs't mentioned sheetanda rim'member connecting the p'e- Q* inforcing mem ripheries of eachof said sheets and prede- Y termining the spacial relation thereof.

2. A soundrcproducerhaving*a diaphragm comprisingala er of Wood, aplurality of reliefs-'extending at angles to each other across said.diaphragm and a see- -ond layer of wood mounted on said reinfor ingmembers in spaced relation to .said first mentioned'layer of wood and arim member 'connecting the peripheries of said layers and opredetermining the spacial relation thereof.

. In testimony whereof I affix my signature.

ERNST HUETER.

o the lattice work are thin, homogenous and elastic and the lattice work

